1. Field of the Invention
The present invention relates to a Darlington circuit comprising a field effect transistor and a bipolar output transistor which are integrated on a semiconductor body of a first conductivity type. The integration of the field effect transistor is undertaken in such a manner that an island-shaped semiconductor region of a second conductivity type is located in the semiconductor body, that a source region of the first conductivity type is located in the island-shaped semiconductor region and that the island-shaped semiconductor region comprises an edge zone extending up to a first principle surface of the semiconductor body and up to the edge of the source region, the edge zone being covered by a gate electrode. As a result, the source region is connected to the base of the output transistor and the emitter of the output transistor is provided with an emitter terminal, and the semiconductor body is provided with a collector terminal which simultaneously forms the drain terminal of the field effect transistor.
2. Description of the Prior Art
A circuit arrangement of the type set forth above is disclosed, for example, in the article "Power Bipolar Devices", by Ph. Leturcq in the periodical "Microelectronic" Reliab., Vol. 24, No. 2, 1982, pp. 313-337, particularly with respect to FIG. 18 on Page 335. In addition to an island-shaped semiconductor region accepting the source region of the field effect transistor, a further such region of the second conductivity type is provided into which an emitter region of the output transistor is embedded, this being connected via an emitter contact to the emitter terminal. The thickness of the semiconductor body is thereby selected smaller than the lateral distance of the drain region of the field effect transistor from the emitter region of the output transistor, whereby the drain region is formed by a sub-region of the semiconductor body which is immediately adjacent to the edge zone of the island-shaped region covered by the gate electrode.